1. Field of the Invention
This invention relates to multi-component dispensing and mixing systems for paints and coatings. More particularly, the present invention relates to devices and methods for packaging, mixing, and dispensing multi-component paints.
2. Related Art
U.S. Pat. No. 5,249,709 discloses cartridges for dispensing reactive materials in predetermined ratios. U.S. Pat. No. 5,072,862 discloses static flow mixers for use in dual cartridges. U.S. Pat. No. 4,538,920 discloses a dual cartridge with a static mixer in the nozzle. U.S. Pat. No. 4,767,026 discloses dual cartridge dispensing and mixing apparatus. U.S. Pat. No. 6,135,631 discloses a static mixer and nozzle for a multiple component dispensing cartridge having at least two cylinders. U.S. Pat. No. 5,535,922 discloses a caulking gun dispenser device, which allows one to use a multi-component cartridge dispenser in a regular caulking gun. U.S. Pat. No. 5,875,928 discloses a two-plunger dispensing gun suitable for mixing and discharging two-component compositions. U.S. Pat. No. 6,244,740 discloses a mixer for multi-component cartridges. U.S. Pat. No. 3,166,221 discloses a plastic, double-tube dispensing container. U.S. Pat. No. 3,828,980discloses a dual cartridge dispenser. U.S. Pat. No. 6,601,782 discloses a disposable spray nozzle assembly.
3. Background of the Technology
The use of high solids coatings is becoming increasingly popular. In the 1970's, regulatory bodies such as the Environmental Protection Agency (EPA) and the California Air Resource Board (CARB) began to scrutinize the paint and coating industries to reduce the amount of Volatile Organic Compounds (VOCs) released into the atmosphere. The regulatory bodies discovered that the solvents contained within paints were contributors to air pollution. The VOCs, which are released as the solvent evaporates from a painted surface during cure, react with nitrogen oxides to form ozone. As a result, the Clean Air Act (CAA) was developed by the EPA to regulate policies concerning the release of large amounts of VOCs into the atmosphere in an attempt to prevent further damage to the environment.
Each year coating application regulations reduce the amount of allowable VOC emissions released from coatings into the atmosphere. The military has begun specifying traditional solvent-based coatings and high solids, edge retentive coatings for construction and repair. These coatings were the government's solution to service life extension and reduced life cycle cost goals while at the same time addressing the tightening regulations. However, with the introduction of this new coating technology, new processes and handling requirements, unfamiliar to painters, were also introduced.
Multi-component, high solids paints cure by a chemical reaction that creates heat after mixing. With the small amount of solvent content, VOCs are greatly reduced, and the coatings provide a higher level of performance. These types of coatings have a much higher viscosity than traditional solvent-based systems, making them very difficult to apply. If the coatings are manually mixed and applied, the pot life of the mixture is shortened dramatically, often as short as 30 minutes and some measured on the order of seconds. Application environment and ratio control have more effect on these coatings than traditional coatings. Pot life, viscosity and curability are all dependant at least in part on temperature and humidity. Painters and supervisors need to continuously monitor these variables to produce the best product, which leads to increased costs.